1. Field of the Invention
Embodiments relate to a focal plane shutter and an imaging apparatus including the same, and more particularly, to a focal plane shutter which has a simple mechanical structure, is easily manufactured and controlled, and provides a live view function, and an imaging apparatus including the focal plane shutter.
2. Description of the Related Art
Digital single lens reflex (DSLR) cameras which produce images at a professional level have recently been widely used. DSLR cameras are SLR cameras capable of taking digital pictures.
The term ‘SLR’ refers to a method of transmitting light bouncing off an object through a single lens either to a viewfinder or to a sensor that may record an image. Commonly used consumer-grade digital cameras are twin lens reflect cameras. Accordingly, an image that may be seen through a viewfinder of a consumer-grade digital camera is different from an image captured by the consumer-grade digital camera.
In a conventional SLR camera, a mirror is placed on an optical axis of a lens to rotate about the optical axis within a predetermined angular range. Under normal conditions, light obtained from the lens is reflected by the mirror, and an image of an object is formed on a focus plate. Thus, a photographer may view the image of the object by using a pentaprism and a viewfinder. In this case, if a shutter-release signal is input, the mirror rotates about a shaft within the predetermined angular range and raises from the optical axis of the lens. Thus, the mirror retreats from the optical axis of the lens. When a shutter is opened under the control of a shutter driving circuit, the image of the object is formed on an imaging device.
In such an SLR camera, the shutter for allowing light to pass for a predetermined period of time is provided in front of the imaging device. The shutter, which is disposed in front of the imaging device, is referred to as a focal plane shutter.
However, a conventional focal plane shutter is connected to a quick return system of the SLR camera and thus has a complicated mechanical structure. As a result, it is not easy to manufacture and control such a conventional focal plane shutter.
Meanwhile, since a lens for use in a DSLR camera may be interchanged with standard lenses which are used in the SLR camera or lenses designed exclusively for digital cameras, suitable lenses may be selectively used according to the preference or objective of a user. Also, since the DSLR camera generally has an imaging device much bigger than that of other conventional digital cameras, occurrence of noise may be prevented under low illumination conditions and a more precise image may be captured.
However, since the mirror is located to cover the imaging device, an image cannot be seen on a liquid crystal display (LCD) during shooting, that is, a live view function is not offered, and the LCD of the DSLR camera may only be used to perform menu manipulation and an image review following image capture. That is, since an image should be seen through an optical viewfinder, the field of view is limited and scenes at various angles including a small angle and a large angle are hidden. Also, when a subject should be looked at furtively for a long time and instantaneously photographed, the DSLR camera is too heavy to hold for a long time in the same position.